I am finally getting serious about loading some BP cartridges for my fine old M1884 Trapdoor, it has an excellent bore and I have high hopes for it (although there is some side-to-side-play in the Buffington sight - another thread to come about that). I have Spence Wolf's authoritative work and I have combed through @Larry Gibson's awesome thread. What a treasure of information and experience from those two sources.
I am starting by following Wolf's recipe using the Lee 405 hb but I am wanting to go rather quickly to target loads more fitted to the rifle so I want to order a custom mould for a 500-gr M1881 arsenal-type bullet.
With this in mind I undertook to slug the barrel and I am a little surprised by the results. I drove my slug through with no problems, it went smoothly, there were no snags or hang-ups from muzzle to breech end. I do not have the special fitting to measure the three grooves diameter so I used the strip of beer can technique. My beer can strip (Yuengling Traditional Ale!) measure a thickness of 0.004". So I wrapped the strip around the bullet and cinched it up snug, held the ends with pliers, and mic'ed it at 0.464". Now if I subtract the two layers of beer can shim that gives (according to my 12 years of advanced education and training) 0.464" - 0.008" = 0.456".
Right? This is a surprise to me because I thought these were all supposed to be between 0.460-0.464?
It occurred to me that perhaps there was 130 years' accumulation of crud in the bore that would make it measure smaller but this rifle is really nice, I bought it from a guy I trust, and the bore looks really good with sharp rifling. I did spend some time cleaning the bore when I got it, and it did not take a whole lot of patching and brushing to get clean patches out of it. And, the bore is easy to clean after shooting BP rounds through it.
Can anyone comment? This just seems smaller than I expected, and a custom mould will be expensive, I want to get it right.
Any comments/advice appreciated,
thanks, namsag.